PAVING MACHINE COMPRISING A PAVING MATERIAL DISTRIBUTION SYSTEM

Description

[0001] This invention relates generally to a roadway construction apparatus and more particularly to a material distribution system for a roadway paving machine.

[0002] A well known problem encountered in asphalt paving is the segregation of aggregate in paving material during transfer and deposition onto a roadway. In particular, separation of the larger aggregate in an asphalt mix from smaller aggregate or "fines" commonly occurs during transfer of the mix from a receiving station, such as a hopper or pickup head on a forward portion of a paving machine, to a lateral spreader, such as an auger, at the rear of the machine. This separation at transfer points commonly occurs because of the tendency of the larger aggregate to roll down an incline formed by the angle of repose of the asphalt mix. The outer edges of a receiving station then receive more coarse aggregate than the inner portion of the receiving station.

[0003] This separation of larger and smaller aggregate in an asphalt mix is the primary cause of two well recognized problems found in asphalt pavements. Vertical segregation, i.e., the uneven distribution of aggregate between the surface and the base of a laid-down mat of asphalt paving material will result in undesirable mat surface properties. Vertical segregation can occur when coarse aggregate rolls forward, toward the front of the paving machine and ahead of the lateral spreader, or auger, and thus becomes the first deposited material on the surface to be paved. The paving material subsequently deposited on top of the coarse aggregate thus contains higher than desirable proportionate amounts of small aggregate and fines. Due to the consequent shortage of larger aggregate at the surface, tire loading during use of the roadway will cause the surface material to flow, especially in the most used tire pathways, resulting in a condition commonly known as rutting.

[0004] A second problem, transverse segregation, more commonly known as "center streak" occurs when a disproportionate amount of the large, or coarse, aggregate is deposited at the center of the mat being formed. This problem occurs when segregated coarse aggregate in the asphalt mix is fed, typically at the transverse center of the paving machine, to the auger distributor and rolls under a centrally disposed auger drive case. The coarse aggregate thus fills this region and inhibits the entrance of smaller aggregate and fines. This produces an area, or strip, of coarse aggregates with few fines to fill voids and bind the mix together. Without the necessary binding materials, the coarse aggregate breaks loose from the road surface, producing a condition commonly known as "ravelling."

[0005] Prior attempts to prevent the segregation of aggregate in an asphalt during deposition of the material on the roadway surface have only been partially successful. For example, some paving machines have a rear frame member than extends downwardly toward the roadway surface to partially deflect the mix and somewhat limit the forward rolling of the mix ahead of the auger. However, since asphalt pavers are commonly loaded on trailers for transport between job sites, the lower edge of the rear frame member must be sufficiently above the roadway surface to provide necessary clearance for ramp loading and unloading of the machine. Thus, due to these loading and transport requirements, the distance between the ground surface and the bottom edge of the rear frame member is such that the ability of the rear frame member to prevent forward rolling of the coarse aggregate, and the consequent vertical separation of aggregate in the paved mat, is severely compromised.

[0006] Prior art documents that more or less show the general level of skill in the art are: DE-A 24 53 748, US-A-4 708 519, and US-A.-3 901 616.

[0007] The present invention is directed to overcoming the problems set forth above. It is desirable to have an effective, economical paving material distribution system that deposits a uniform, unsegregated mixture of paving material on a base surface. It is also desirable to have such a distribution system that prevents separation of coarse aggregate from an asphalt mix during deposition and thus avoids the problems of rutting and ravelling. Further, it is desirable to have an effective paving material distribution system that may be raised to provide sufficient clearance so that a paving machine carrying the distribution system may be driven up a steep ramp, such as a trailer loading ramp.

[0008] The invention is defined in claim 1.

[0009] Preferred embodiments are disclosed in the dependent claims.

[0010] In accordance with one aspect of the present invention, a paving material distribution system for uniformly distributing a layer of paving material along a pathway having a predetermined width, is carried on a paving machine having a rear frame member, and includes a paving material containment member having a length substantially equal to the width of the pathway being paved. The containment member has a bottom edge extending continuously along the entire length of the containment member and is slidably mounted on the rear frame member of the paving machine. The distribution system also includes first means for conveying paving material across the width of the layer of paving material. The first means has a total length substantially equal to the length of the containment member, and has a first side that is positioned at a preselected distance from the containment member. The distribution system further includes power means for controllably, simultaneously moving the containment member and the first means in a substantially vertical direction.

[0011] Other features of the paving material distribution system include a second means that cooperates with the containment member to define a chamber for receiving paving material and providing a reservoir for maintaining a preselected volume of paving material above the first means.

Fig. 1 is an isometric view of a paving machine having a paving material distribution system embodying the present invention;

Fig. 2 is a partial elevational view of the paving material distribution system embodying the present invention; and

Fig. 3 is a cross-sectional view of the paving material distribution system embodying the present invention, taken along the line 3-3 of Fig. 2.

[0012] In the preferred embodiment of the present invention, a paving material distribution system 10 is mounted on a rear frame member 12 of a paving machine 14. In the interest of clarity, a screed assembly 16, normally towed behind the paving machine 14, is shown in phantom lines in Fig. 1. A partial section of the screed assembly 16 is shown in Fig. 3.

[0013] The paving material distribution system 10 includes a paving material containment member 18 that is slidably mounted on the rear frame member 12 of the paving machine 14. The containment member 18 is preferably a metal plate having a pair of vertically oriented slots 20,20' positioned near the outer ends of the containment member. The slots 20,20' cooperate with a pair of bolts 22,22' threaded into the rear frame member 12 to provide guide surfaces for alignment of the containment member 18. The bolts 22,22' may be tightened after the distribution system 10 is elevationally positioned on the rear frame member 12 to maintain a bottom edge 24 of the containment member 18 and, as described below, other attached elements of the distribution system at a desired fixed elevation above a surface 26 on which the paving machine 14 is supported. Preferably, the bottom edge 24 extends continuously along the entire length of the containment member 18.

[0014] The length of the paving material containment member 18 is substantially equal to the width of a layer of paving material distributed by the distribution system 10 along a pathway that is determined by the direction of travel of the paving machine 14. Depending on the arrangement and construction of the screed system 16, the width of the layer of paving material distributed by the distribution system 10 may extend either totally, or somewhat less than totally, between the actual outside edges of a mat shaped by the screed system. In arrangements where the distribution system does not extend completely to the actual outside edges of the mat, the screed system moves a sufficient amount of paving material laterally to fill the area between the outer end of the distribution system and the outside edge of the mat. Thus, as used herein in the specification and the claims, the term "a length substantially equal to the width of the layer of paving material" means a length that is sufficient to effectively distribute paving material uniformly across the width of the mat, and may be either the actual total distance between the outside mat edges or somewhat less than the actual total distance between outside mat edges.

[0015] The paving material distribution system 10 also includes a first means 30 for conveying paving material in preselected directions across the width of the layer of paving material and has a length that is substantially equal to the length of the containment member 18. Preferably, the first means 30 includes an auger drive assembly 32 having a pair of bearing supports 34,36 mounted in a lower portion of the drive assembly 32. The first means also includes separate left and right augers 38,40 that are rotatably mounted at their inboard ends in a respective one of the bearing supports 34,36, and at their outboard ends by respective bearing supports 42,44. A pair of hydraulic motors 46 are mounted on an upper portion of the auger drive assembly 32 and are connected through drive chains to a respective one of the augers 38,40. In the interest of clarity, an upper portion of the auger drive assembly 32 is broken away in Figs. 1 and 2 to show details that will be later described. Thus, although there is an hydraulic motor mounted on each side of the drive assembly 32, only the motor on the left side of the drive assembly is shown in the drawings. The rotational speed of the motors 46 is controlled to rotate the augers 38,40 at the same speed or, if required, at different speeds to distribute a selected amount of paving material along the axis of the augers. Each of the augers 38,40 have a first side 50 facing the containment member 18, a second, or opposite, side 52 facing the screed system 16, and a bottom side 54 facing roadway surface 26.

[0016] Typically, a prepared mix of paving material is transferred from a surge bin or pickup head, not shown, at the front of the paving machine 14 to a lateral spreader at the rear of the machine. In the illustrative embodiment associated with the present invention, paving material is transferred, or fed, to the paving material distribution system 10 by one or more feeder conveyors 56,56' through openings 58,58' in the rear frame member 12 of the paving machine 14. It is recognized that whenever a material containing a mixture of differently sized particles is transferred in this manner, there is a tendency for the larger sized particles to separate, or become segregated, from the smaller sized particles. Furthermore, if the paving material fed by the feeder conveyors 56,56' to the augers 38,40 is permitted to roll ahead of the augers during lateral distribution of the material across the mat, additional segregation will occur, and the segregated larger aggregate roll forwardly and be the first material deposited on the roadway surface 16. The remaining pavement mixture containing a disproportionately large amount of small aggregate and fines will then be deposited on top of the first deposited larger aggregate. Thus, the finished pavement mat will have an uneven distribution of aggregate from its surface to its base. This vertical segregation of aggregate in the mat is a defect and, as described above, produces the undesirable condition commonly known as rutting.

[0017] Therefore, in carrying out the present invention, it is particularly important that the distance between the first side 50 of the first means 30, i.e., the side of the augers 38,40 facing the containment member 18, and the containment member 18 be controlled to assure that the paving material mixture will be prevented from rolling ahead of the augers. Preferably, this distance should be between about 1 to about 1.5 times the nominal diameter of the largest aggregate in the paving material being distributed by the first means 30.
In an illustrative embodiment of the present invention, the distance between the first side 50 of the first means 30 and the containment member 18 is about 2 inches (5 cm).

[0018] To further avoid the problem of vertical segregation of aggregate in the finished mat, it is important that paving material not roll ahead of the augers 38,40. To prevent the unconstrained forward rolling of the mix ahead of the augers it is desirable that the bottom edge 24 of the containment member 18 be substantially level with the bottom side 54 of the first means 30. That is, the bottom edge 24 of the containment member 18 should be maintained at substantially the same elevation as the side of the augers 38,40 facing the roadway surface 26.

[0019] Although it would be desirable to have the bottom edge 24 of the containment member 18 in virtual contact with the roadway surface 26, this is not practical in actual use due to the presence of raised obstacles in the path of the paving machine, such as manhole covers of raised sections. To overcome this problem, it is desirable that the paving material distribution system have a deflectable flap member 60 attached to the bottom edge 28 of the containment member 18 that extends substantially along the entire length of the containment member. Also, the deflectable flap member 60 should have a height sufficient to extend from the bottom edge 24 of the containment member 18 to the roadway surface 16. The flap member 60 may conveniently be constructed of a flexible rubber belting material, or be a rigid metal member that is mounted on the containment member with deflectable spring connectors.

[0020] The paving material distribution system 10 embodying the present invention also preferably includes a second means 62 that cooperates with the containment member 18 to define a chamber 64 for receiving paving material and providing a reservoir for maintaining a preselected volume of paving material above the first means 30. In the preferred embodiment of the present invention, the second means 62 includes a rear plate 66 having spaced apart end portions 68,68' The rear plate 66 is attached in a spaced relationship to the containment member 18 by a pair of side plates 70,72 which extend from the spaced apart end portions 68,68' of the rear plate 66 to the containment member 18. The containment member 18, rear plate 66, and the side plates 68,68' thus cooperate to form the chamber 64 which, in the preferred embodiment, is essentially a four sided hopper or chute having an open top adjacent the discharge opening 58,58', and an open bottom positioned directly above the first means 30. In operation the amount of paving material fed to the chamber 64 is determined by the speed of the feeder conveyors 56,56', which are controlled to assure that a head, or supply, of paving material is maintained in the chamber.

[0021] Importantly, the chamber 64 is positioned immediately above the first means 30. To prevent the free flow of paving material rearwardly of the augers 38,40 to a "dead zone" between the augers and the screed system 16, it is desirable that the rear plate 66 forming the chamber 64 be spaced from the containment member 18 a distance not greater than the distance that the second side 52 of the first means 30 is spaced from the containment member. That is, the rear plate 66 should not be positioned behind the side of the augers 38,40 facing the screed system 16. To further restrict the possible segregation of paving material by larger aggregate rolling from the chamber 64 to the "dead zone" between the augers and the screed system, a flap member 74 constructed of a flexible rubber belting material may be advantageously attached to a lower edge of the rear plate 66.

[0022] The paving material distribution system 10 also includes power means 76 for controllably, simultaneously moving the containment member 18, the first means 30, and the second means 62 in a substantially vertical direction. In the preferred embodiment of the present invention, the power means 76 includes a support beam 78 that extends across the rear of the paving machine 14. The auger drive assembly 32 of the first means 30 is directly attached to the support beam 78, and the rear plate 66 of the second means 62 is fixedly attached to the auger drive assembly 32. Additionally, the containment member 18 is attached to the support beam by spacers 80, one of which is shown in Fig. 3. The spacers 80 are disposed between the support beam and the containment member near their respective outboard ends.

[0023] The support beam 78 also has a pair of auger support struts 82,82' extending downwardly from the outer ends of the support beam 18. The outboard bearing supports 42,44 are carried in respective lower portions of the struts 82,82' and rotatably support the augers 38,40 in fixed spaced relationship with respect to the support beam 78. Thus, the containment member 18, the first means 30, and the second means 62 are all operatively connected to the support beam 78 and consequently move simultaneously with each other and with the support beam.

[0024] Vertical movement of the support beam 78 is provided by a hydraulic cylinder 84 having a first end 86 attached through a pin connection to the rear frame member 12 and a second end 82 attached through a second pin connection to the support beam 78. The hydraulic cylinder 84 is provided, in the manner well known in the hydraulic actuator art, with a controllable source of pressurized hydraulic fluid to extend and retract the cylinder, thus raising and lowering the support beam 78 and the paving material distribution system 10 attached thereto.

[0025] Vertical movement of paving material distribution system 10 is guided by a guideway 90 attached to the rear frame member 12 of the paving machine 14. Typically, the guideway 90 comprises a T-slot arrangement in which a T-shaped guide member 92 extends outwardly from the support beam toward the rear frame member 12 and slidably engages mating slots in the guideway 90. Desirably, a plurality of openings 94 are be provided through the sides of the guideway 90 to permit insertion of a locking pin, not shown, through the guideway and through associeated holes in the T-shaped guide member 92. In this manner, the paving material distribution system 10 may be locked at a fixed elevation if desired, such as when loading or transporting the paving machine 14.

[0026] Alternatively, the power means 76 may comprise a pair of hydraulic cylinders, each of which may be attached to a respective outboard end of the support beam 78. Also, if desired, two laterally spaced guideways and guide members may be provided to provide alignment of the distribution system 10 during vertical movement instead of the single guideway and guide member described above. Further, combinations of single or multiple hydraulic cylinders, and guideways and guide members, may be used in carrying out the present invention.

[0027] In operation, paving material is transferred from a forward bin or pickup head by the feeder conveyors 56,56' to the chamber 64 of the distribution system 10. As described above, the feeder conveyors deliver paving material to the chamber 64 and maintain a reservoir, or head, of the paving material in the chamber 64, positioned above the augers 38,40. The paving material flows from the chamber 64 by gravity feed onto the augers 38,40 and is carried laterally along the axis of the augers toward both the center and the outer edges of the mat being shaped by the rearwardly disposed screed system 16. Falling of segregated paving material directly onto the roadway surface 16 and rolling of segregated paving material ahead of the augers 38,40 is prevented by the horizontal and vertical position of the continuous containment member 18 in front of the augers. Importantly, the height of the bottom side of the augers 38,40 and the bottom edge 24 of the containment member 18 above the roadway surface 16, and accordingly the depth of paving material distributed in front of the trailing screed system 16, is adjustably controlled simultaneously by appropriate extension or retraction of the hydraulic cyliner 84.

[0028] In typical asphalt paving operations, the paving material distribution system 10 embodying the present invention advantageously distributes a uniform, nonsegregated mixture of paving material on a roadway surface 26 ahead of a towed screed system 16. Thus, vertical and transverse segregation of aggregate in the paved mat are averted, and the resultant problems of rutting and ravelling are avoided.

[0029] The present invention is also adaptable for use with relatively wide or variable width paving applications wherein extensions on the outboard ends of the containment member 18 and the augers 38,40 can effectively move the paving material transversely while simultaneously preventing the forward rolling of segregated paving material.

[0030] The paving material distribution system embodying the present invention is also capable of being raised as a unit, independently of the paving machine main frame and any associated screed systems, to permit the paving machine to be driven up steep ramps for loading.

Claims

1. A paving machine (14) comprising a paving material distribution system (10) for uniformly distributing a layer of paving material along a pathway having a predetermined width, said paving material containing aggregate having a predetermined maximum nominal diameter, said pathway being determined by a forward direction of travel of said paving machine, and said predetermined width of said layer of paving material being defined as the distance across said layer in a direction transverse to the forward direction of travel of said paving machine, said paving material distribution system (10) comprising:

a paving material containment member (18) having a length substantially equal to the width of said layer of paving material and a bottom edge (24) extending continuously along the entire length of said containment member (18), said containment member (18) being slidably mounted on a rear frame member (12) of said paving machine (14);

a rotatable auger (38, 40) mounted on said paving machine (14) for conveying paving material in preselected directions across the width of said layer of paving material, said auger (38, 40) having a total length substantially equal to the length of said containment member (18) and first, second and bottom sides, said first side being positioned at a preselected distance in a direction opposite to said forward direction of travel of said paving machine (14) from said containment member (18), and

power means (76) for controllably, simultaneously moving the containment member (18) and the rotatable auger (38, 40) in a substantially vertical direction.

2. A paving machine as set forth in claim 1, wherein said paving material distribution system (10) includes means (62) cooperating with said containment member (18) and defining a chamber for receiving paving material and providing a reservoir for maintaining a preselected volume of paving material above said rotatable auger (38, 40), and wherein said power means (76) moves said means (62) controllably and simultaneously with the movement of said containment member (18) and said rotatable auger (38, 40).

3. A paving machine as set forth in claim 1 or 2, wherein the distance between the first side of said rotatable auger (38, 40) and the containment member (18) is in the range of 1 to 1.5 times the nominal diameter of the largest aggregate in the paving material conveyed by said rotatable auger (38, 40).

4. A paving machine as set forth in claim 3, wherein said distance is about 5 cm (2 inches).

5. A paving machine as set forth in any of claims 1 to 4, wherein a bottom edge of the containment member (18) is maintained at substantially the same elevation as the bottom side of said rotatable auger (38, 40).

6. A paving machine as set forth in claim 5, wherein said paving material distribution system includes a deflectable flap member (60) attached to said bottom edge of the containment member, said flap member (60) having a length extending substantially along the entire length of said containment member (18).

7. A paving machine as set forth in claim 1, wherein an auger drive assembly is operatively attached to said power means (76) and having a pair of bearing supports mounted therein, a pair of auger (38, 40) each being rotatably mounted in a respective one of said bearing supports, and a pair of hydraulic motors (46) each being operatively connected to a respective one of said augers.

8. A paving machine as set forth in claim 1, wherein said power means includes a support beam operatively connected to said containment member (18) and said auger (38, 40), and a hydraulic cylinder (84) having first and second ends, said first end of said cylinder being attached to the rear frame member (12) of said paving machine, and said second end of said cylinder being attached to said support beam.

9. A paving machine as set forth in claim 2, wherein said means (62) includes a rear plate (66) spaced from said containment member (18) and having spaced apart end portions, and a pair of side plates each of which extend from a respective one of the end portions of said rear plate to said containment member.

10. A paving machine as set forth in claim 9, wherein the rear plate of said means (62) is spaced from said containment member at a distance not greater than the distance of the second side of said auger (38, 40) from said containment member.

Ansprüche

1. Straßenfertiger (14), der ein Fahrbahnmaterialverteilungssystem aufweist, zum gleichförmigen Verteilen einer Schicht von Fahrbahnmaterial entlang einer Bahn mit einer vorbestimmten Breite, wobei das Fahrbahnmaterial ein Aggregat oder Stoffmaterial mit einem vorbestimmten maximalen Nenndurchmesser enthält und die Bahn durch eine Vorwärts-Laufrichtung des Straßenfertigers bestimmt wird, und wobei die vorbestimmte Breite der Schicht aus Fahrbahnmaterial als der Abstand über die erwähnte Schicht in einer Richtung quer zur Vorwärtsrichtung des Laufs des Straßenfertigers definiert wird, und wobei das Fahrbahnmaterialverteilungssystem (10) folgendes aufweist:

ein Fahrbahnmaterial-Umschließungsglied (18) mit einer Länge im wesentlichen gleich der Breite der Schicht aus Fahrbahnmaterial und mit einer Bodenkante (24), die sich kontinuierlich entlang der gesamten Länge des Umschließungsgliedes (18) erstreckt, wobei das Umschließungsglied (18) gleitend an einem hinteren Rahmenglied (12) des Straßenfertigers (14) angebracht ist;

drehbare Bohr- oder Schnecken- bzw. Schraubenmittel (38, 40) angebracht an dem Straßenfertiger (14) zum Transport von Fahrbahnmaterial in vorgewählten Richtungen über die Breite der Schicht aus Fahrbahnmaterial hinweg, wobei die Bohr- oder Schneckenmittel (38, 40) eine Gesamtlänge besitzen, die im wesentlichen gleich der Länge des Umschließungsgliedes (18) ist, sowie erste, zweite und untere Seiten,

wobei die erste Seite mit einem vorgewählten Abstand in einer Richtung entgegengesetzt zur Vorwärtsrichtung des Laufs des Straßenfertigers (14) vom Umschließungsglied (18) angeordnet ist, und

Leistungsmittel (76) zum steuerbaren gleichzeitigen Bewegen des Umschließungsglieds (18) und der drehbaren Schraubenmittel (38, 40) in einer im wesentlichen vertikalen Richtung.

2. Straßenfertiger nach Anspruch 1, wobei das Fahrbahnmaterialverteilungssystem (10) Mittel (62) aufweist, die mit dem Umschließungsglied (18) zusammenarbeiten und eine Kammer zur Aufnahme von Fahrbahnmaterial definieren und ein Reservoir vorsehen zum Aufrechterhalten eines vorgewählten Volumens an Fahrbahnmaterial oberhalb der drehbaren Bohr- oder Schrauben- bzw. Schneckenmittel (38, 40), und wobei die Leistungsmittel (76) die Mittel (62) steuerbar und gleichzeitig mit der Bewegung des Umschließungsglieds (18) und der drehbaren Schraubenmittel (38, 40) bewegen.

3. Straßenfertiger nach Anspruch 1 oder 2, wobei der Abstand zwischen der ersten Seite der drehbaren Bohr- oder Schraubenmittel (38, 40) und dem Umschließungsglied (18) im Bereich des 1- bis 1,5-fachen des Nenndurchmessers des größten Aggregats oder Stoffmaterials im Fahrbahnmaterial ist, das durch die drehbaren Schraubenmittel (38, 40) transportiert wird.

4. Straßenfertiger nach Anspruch 3, wobei der Abstand ungefähr 5 cm (2 Zoll) beträgt.

5. Straßenfertiger nach einem der Ansprüche 1 bis 4, wobei eine Bodenkante des Umschließungsglieds (18) auf im wesentlichen der gleichen Höhe gehalten wird, wie die Bodenseite der drehbaren Bohr- oder Schraubenmittel (38, 40).

6. Straßenfertiger nach Anspruch 5, wobei das Fahrbahnmaterialverteilungssystem ein auslenkbares Klappenglied (60) aufweist, welches an der Bodenkante des Umschließungsglieds angebracht ist und wobei das Klappenglied (60) eine Länge besitzt, die sich im wesentlichen entlang der gesamten Länge des Umschließungsgliedes (18) erstreckt.

7. Straßenfertiger nach Anspruch 1, wobei eine Bohr- oder Schneckenmittel-Antriebsanordnung betriebsmäßig an den Leistungsmitteln (76) angebracht ist und ein Paar von darin angebrachten Lageranordnungen aufweist, und wobei ein Paar von Schraubenmitteln (38, 40) jeweils drehbar in einer entsprechenden der Lageranordnungen gelagert ist und ein Paar von hydraulischen Motoren (46) jeweils betriebsmäßig mit einem entsprechenden der Bohr- oder Schraubenmittel verbunden ist.

8. Straßenfertiger nach Anspruch 1, wobei die Leistungsmittel einen Stützträger aufweisen, der betriebsmäßig mit dem Umschließungsglied (18) und den Schraubenmitteln (38, 40) verbunden ist, und mit einem hydraulischen Zylinder (84) mit ersten und zweiten Enden, wobei das erste Ende des Zylinders an dem hinteren Rahmenglied (12) des Straßenfertigers angebracht ist, während das zweite Ende des Zylinders an dem erwähnten Stützträger angebracht ist.

9. Straßenfertiger nach Anspruch 2, wobei die Mittel (62) eine hintere Platte (66) beabstandet gegenüber dem Umschließungsglied (18) aufweisen, und zwar mit beabstandeten Endteilen und ferner mit einem Paar von Seitenplatten, deren jede sich von einem entsprechenden der Endteile der hinteren Platte aus erstreckt, und zwar zu dem Umschließungsglied.

10. Straßenfertiger nach Anspruch 9, wobei die hintere Platte der Mittel (62) von dem Umschließungsglied beabstandet ist, und zwar mit einem Abstand der nicht größer ist als der Abstand der zweiten Seite der Schraubenmittel (38, 40) gegenüber dem Umschließungsglied.

Revendications

1. Machine routière (14) comprenant un système de distribution de matériau de revêtement routier (10) pour répartir uniformément une couche de matériau de revêtement le long d'une voie de largeur prédéterminée, le matériau de revêtement contenant un agrégat de diamètre nominal maximum prédéterminé, la voie étant déterminée par une direction de déplacement vers l'avant de la machine routière et la largeur prédéterminée de la couche de matériau de revêtement étant définie comme la distance en travers de cette couche dans une direction transverse à la direction de déplacement vers l'avant de la machine routière, le système de distribution de matériau de revêtement (10) comprenant :

un élément de refoulement de matériau de revêtement (18) ayant une longueur sensiblement égale à la largeur de la couche de matériau de revêtement et un bord inférieur (24) s'étendant de façon continue sur toute la longueur de l'élément de refoulement (18), l'élément de refoulement (18) étant monté à coulissement sur un élément de châssis arrière (12) de la machine routière (14) ;

une vis tournante (38, 40) montée sur la machine routière (14) pour transporter le matériau de revêtement dans des sens prédéterminés selon la largeur de la couche de matériau de revêtement, ladite vis (38, 40) ayant une longueur totale sensiblement égale à la longueur de l'élément de refoulement (18) et des premier et second côtés et un côté inférieur, le premier côté étant disposé à une distance prédéterminée dans une direction opposée à la direction de déplacement vers l'avant de la machine routière (14) à partir de l'élément de refoulement (18) ; et

un moyen d'entraînement (76) pour déplacer simultanément et de façon commandable l'élément de refoulement (18) et la vis tournante (38, 40) dans une direction sensiblement verticale.

2. Machine routière selon la revendication 1, dans laquelle le système de distribution de matériau de revêtement (10) comprend des moyens (62) coopérant avec l'élément de refoulement (18) et définissant une chambre pour recevoir le matériau de revêtement et constituer un réservoir pour maintenir un volume prédéterminé de matériau de revêtement au-dessus de la vis tournante (38, 40) et dans laquelle le moyen d'entraînement (76) déplace lesdits moyens (62) de façon commandable et simultanément au déplacement de l'élément de refoulement (18) et de la vis tournante (38, 40).

3. Machine routière selon la revendication 1 ou 2, dans laquelle la distance entre le premier côté de la vis tournante (38, 40) et l'élément de refoulement (18) se trouve dans une plage de 1 à 1,5 fois le diamètre nominal du plus grand agrégat dans le matériau de revêtement transporté par la vis tournante (38, 40).

4. Machine routière selon la revendication 3, dans laquelle ladite distance est d'environ 5 cm (2 pouces).

5. Machine routière selon l'une quelconque des revendications 1 à 4, dans laquelle un bord inférieur de l'élément de refoulement (18) est maintenu à sensiblement la même élévation que le bord inférieur de la vis tournante (38, 40).

6. Machine routière selon la revendication 5, dans laquelle le système de distribution de matériau de revêtement comprend un élément de volet pouvant être défléchi (60) fixé au bord inférieur de l'élément de refoulement, cet élément de volet (60) ayant une longueur qui s'étend sensiblement sur toute la longueur de l'élément de refoulement (18).

7. Machine routière selon la revendication 1, dans laquelle un ensemble d'entraînement de vis est fixé de façon opérative au moyen d'entraînement (76) et comporte une paire de supports de palier qui y sont montés, une paire de vis (38, 40) dont chacune est montée à rotation dans l'un respectif des supports de palier, et une paire de moteurs hydrauliques (46) dont chacun est opérativement relié à l'une respective des vis.

8. Machine routière selon la revendication 1, dans laquelle le moyen d'entraînement comprend une poutre support opérativement reliée à l'élément de refoulement (18) et à la vis (38, 40), et un vérin hydraulique (84) ayant des première et seconde extrémités, la première extrémité du vérin étant fixée à l'élément de châssis arrière (12) de la machine routière et la seconde extrémité du vérin étant fixée à la poutre support.

9. Machine routière selon la revendication 2, dans laquelle lesdits moyens (62) comprennent une plaque arrière (66) espacée de l'élément de refoulement (18) et ayant des parties d'extrémité espacées et disjointes, et une paire de plaques latérales dont chacune s'étend à partir de l'une respective des parties d'extrémité de la plaque arrière vers l'élément de refoulement.

10. Machine routière selon la revendication 9, dans laquelle la plaque arrière desdits moyens (62) est espacée de l'élément de refoulement d'une distance non supérieure à la distance du second côté de la vis (38, 40) par rapport à l'élément de refoulement.

Drawing